This invention relates to electrical connectors, and particularly to high-speed electrical connectors for attachment to printed circuit boards.
Electrical conductors carrying high-frequency signals and currents are subject to interference and cross-talk when placed in close proximity to other conductors carrying high-frequency signals and currents. The interference and cross-talk can result in degradation of the signal and errors in signal reception. Coaxial and shielded cables are available to carry signals from a transmission point to a reception point, and reduce the likelihood that the signal carried in one shielded or coaxial cable will interfere with the signal carried by another shielded or coaxial cable in close proximity. However, at points of connection, the conductor shielding is often lost. The loss of shielding allows interference and crosstalk between signals near the points of connection. The use of individual shielded wires and cables is not desirable at points of connection due to the need for making a large number of connections in a very small space. In these circumstances, two-part high-speed backplane electrical connectors containing multiple shielded conductive paths are used. For example, specification IEC 1076-4-101 from the International Electrotechnical Commission sets out parameters for 2 mm, two-part connectors for use with printed circuit boards.
As users modify and upgrade systems to achieve improved performance, problems continue to arise. In particular, with many high-frequency systems, even a small unshielded portion of an electrical conductor causes a discontinuity in the impedance of the conductor, and allows performance damaging interference and cross-talk to occur. A connector system that provides improved shielding and impedance control is desirable.